Automatic Transmission Abnormality Gear Shift Control
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Solution Overview
Problem
In multiple-speed automatic transmissions with planetary gear type stepped systems, failures in frictional engaging elements lead to significant worsening of driving performance due to large gear shift stage differences, particularly between the first and fifth speeds, and result in increased data capacity requirements for control data during abnormal states.
Innovation Solution
The implementation of an automatic transmission system that includes a plurality of planetary gears and frictional engaging elements, with a control method that detects abnormal states and shifts between gear shift stages by forcefully releasing specific frictional engaging elements, allowing the use of intermediate gear shift stages not typically used in normal operation, thereby preventing performance degradation and minimizing data capacity increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control data for special gear shift stages is added to handle frictional element failures, then driveability during abnormality is improved, but data capacity requirements increase significantly
Solution Approach 1:
The patent makes existing gear shift control data serve multiple functions by reusing it for both normal operation and abnormality handling. The same control data is applied to achieve special gear shift stages during frictional element failures, eliminating the need for separate dedicated control data for abnormal conditions.
Solution Approach 2:
The patent changes the operational parameters of existing gear shift stages by selectively disabling unavailable stages and reconfiguring the transmission to use alternative stages. This allows the system to adapt to frictional element failures by modifying which stages are accessible rather than creating new control data.
2Device complexity
If gear shift stages are limited to only first, fifth, and seventh speeds during frictional element failure, then control simplicity is maintained, but traveling performance deteriorates significantly
Solution Approach 1:
The patent dynamically adjusts the available gear shift stages based on the operational state of frictional elements. When failures occur, the system flexibly reconfigures which stages can be used, allowing intermediate stages to become accessible through alternative control sequences, thereby maintaining better traveling performance without excessive complexity.
3Productivity
If intermediate gear shift stages are made available during abnormality, then traveling performance is improved, but control data requirements increase
Solution Approach 1:
The patent makes existing gear shift control data serve multiple functions by reusing it for both normal operation and abnormality handling. The same control data is applied to achieve special gear shift stages during frictional element failures, eliminating the need for separate dedicated control data for abnormal conditions.
Data Source
AI summary
In a planetary gear type stepped automatic transmission, a gear shift control to shift a gear shift stage between a first gear shift stage and a second gear shift stage is performed by a first shift control section by referring to a first gear shift control data used when the gear shift stage is switched between the first gear shift stage and the second gear shift stage, an abnormality state due to a failure of at least one of a first frictional engaging element and a second frictional engaging element is detected, and an abnormality state gear shift control is performed to shift the gear shift stage between a third gear shift stage (for example, first speed) and a fourth gear shift stage (for example, 2.5 speed) by the first shift control section, while forcefully releasing the first frictional engaging element, when detecting the abnormality state.